Washing apparatus with tub sealing system



May 27, 1958 L. w. GUTH WASHING APPARATUS WITH TUB SEALINGDSYSTEM Filed Dec. 14, 1955 INVENTOR.

LAUREN w. GUTH HIS ATTO NEY WASHING APPARATUS WITH TUB SEALING SYSTEM Lauren W. Guth, Louisville, Ky, assignor to General Eiectric Company, a corporation of New York Application December 14, 1955, Serial No. 553,087

4 Claims. (Cl. 134-57) This invention relates to washing apparatus such as dishwashers and the like, and more particularly to an improved tub sealing system for such apparatus.

Dishwashers of the type having a washing vat or tub mounted for horizontal movement into and out of a cabinet structure and provided with a top access opening have several advantages over dishwashers of other types, such as those provided with a front opening door hinged along its bottom edge. Among these advantages are better accessibility and more positive fluid tight sealing around the cover closing the access opening. However, the mechanical linkage arrangements which have been used in known top opening dishwashers for securing the cover in sealing engagement with the tub have not always been completely satisfactory because close tolerances are required to secure a tight fit, and means for adjustment may be required to compenstate for decreasing resilience, of the sealing gaskets commonly employed.

According, a primary object of the present invention is to provide an improved cover sealing system for washing apparatus in which cover sealing linkages are eliminated and adjustment means are unnecessary.

Another object of this invention is to provide a cover sealing system for washing apparatus which utilizes hydraulic pressure as the means for insuring sealing engagement between the cover and the top peripheral edge of the tub forming the washing compartment.

A further object of this invention is to provide a cover sealing system for dishwashers or the like in which the cover for the washing tub remains stationary with respect to the cabinet in which the tub is mounted and sealing is achieved by an inflatable gasket secured to the cover.

Further objects and advantages of this invention will becomeapparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Briefly stated, in accordance with one form of my invention the foregoing objectives are achieved by providing an inflatable gasket secured to the periphery of a fixed cover mounted in the dishwasher cabinet so as to engage the peripheral edge of the dish holding tub, and a fluid inlet and outlet system for the gasket controlled by an electrical circuit inter-connected with the usual dishwasher sequence control circuit.

For a better understanding of my invention, reference may be made to the accompanying drawing in which:

Fig. 1 is an elevation view, partly in section, of a dishwasher embodying my invention.

Fig. 2 is similar to Fig. 1 but shows the tub of the dishwasher in its extended position.

Fig. 3 is a schematic circuit diagram illustrating the control system of my invention.

Referring to the drawing, numeral 1 designates a cabinet in which a dish holding vat or tub 2 is supported for sliding horizontal movement by means of a sliding support structure including slide member 3 secured to tub 2 rates Patent and rollers 4 mounted on the cabinet. Thus tub 2 may be withdrawn to the position shown in Fig. 2 in which dishes may be loaded and unloaded, after which it may be returned to the storage or washing position 'as shown in Fig. l. The top access opening of tub 2 is closed by a cover 5 which, in accordance with the present invention is fixedly secured in the upper portion of cabinet 1, so as to overlie tub 2 when the latter is in its closed position.

Dishwashers of the general type herein disclosed include a water circulating system so arranged that water is automatically admitted to tub 2 at the beginning of each rinsing or washing cycle, circulated therein for a predetermined period of time and then automatically discharged from the tub. In the dishwasher illustrated in the drawing, water is admitted to tub 2 through an inlet conduit 6 adapted for connection to a suitable water supply system, an electrically actuated inlet control valve 7, a pressure relief check valve 8 whose function will be described in greater detail below, and a discharge conduit 9 which terminates in an open end aligned with a funnel 10 secured to and communicating with tub 2, when the tub is in the position shown in Fig. l. Tub 2 is equipped with suitable means for circulating washing fluid therein such as an impeller (not shown) at the bottom of the tub driven by an electric motor 11, and with electrically actuated drain means such as a motor driven drain pump 12 adapted to drain tub 2 at the end or" each washing or rinsing cycle. impeller motor 11 and drain pump 12 are sequentially operated by means of a time switch or timer 13 so as to provide a series of washing operations. Timer 13 may be of the type which includes a rotary control knob 14 provided with suitable indicia for indicating the steps in the washing program.

in order to make the washing compartment formed by tub 2 and cover 5 a fluid tight compartment, resilient gasket 15 is secured to the periphery of cover 5 so as to provide a fluid tight seal when its sealing surface 16 is in engagement with a peripheral flange 17 around the opening of the tub. In accordance with the present invention, gasket 16 is a hollow inflatable gasket connected to' a hydraulic system adapted to maintain sealing surface 16 in contact with flange 17 during washing operations. The hydraulic system for gasket 15 may be conveniently connected with the water inlet system for tub 2, and as shown in Fig. 1 may include a conduit 18 inter-connecting inlet conduit 6 and gasket 15 so that water is supplied thereto whenever inlet valve 7 is open. Water pressure within gasket 15 is limited to a relatively low value, such as three pounds per square inch for example, by pressure relief valve 3, which as described above is connected in the water inlet line between inlet valve 7 and discharge conduit 9. finally, the hydraulic system for sealing gasket 15 includes a mechanically actuated venting valve 19 connected between conduits 9 and 18, and provided with a push rod linkage 20 so arranged that valve 19 may be actuated to its open position by depressing button Zila, and to its closed position by depressing button 20b.

Referring to Fig. 3 in which the electrical control system of the present invention is schematically illustrated, time switch 13 includes main power switch 13:: which is closed whenever control knob 14 is moved from its off position to any position within the washing operation program, a Water inlet valve control switch 21 in series with inlet valve 7, an impeller motor control switch 22, and a drain pump control switch 23. It will, of course, be understood that timer switches 21, 22 and 23- are operated in a suitable predetermined sequence so as to provide suit able filling, washing, rinsing, and draining operations and thus provide a complete washing cycle. Further it will be noted that all of the components controlled by the timer switches as well as the timer itself are 7 parts thus being in the position shown in Fig. 1.

energized throughmain power switch 13 and that the V 7 main power switch is connected to the power source master switch 24 and a mechanical interlock switch 2 5'. As illustrated inthe drawing; master switch 24 is operated I designated by power supply lines L and L through a by push rod linkage 2t) and is movable to its closed position simultaneously with closure of venting valve 19, so that the dishwater energizing circuit may be energized only when valve 19 is in its closed position. Interlock switch 25 is, of course, positioned within cabinet 1 so as to be moved to its closed position whenever tab 2 is in the closed position shown in Fig. 1.

To provide for the immediate sealing of gasket and tub, 2 at the beginning of a washing operation, and to insure that the necessary sealing pressure is maintained within the gasket throughout each washing operation, a pressure switch 26 responsive to the pressure within gasket 15 is provided. Pressure switch 26 includes'a movable contact 27 electrically connected to switch 13a, a'flgred contact 23 electrically connected in circuit with inlet valve 7 and a fixed contact 29 through which timer switches 22 and 23. are energized. Pressure switch 26 is shown in Fig. 3 in its zero pressure position, in which movable contact 27 is in engagement with fixed contact 23 so that inlet valve 7 will be energized upon closure of main power switch 13a and master switch 24, However, during normal washing operations movable contact 27 is in engagement with fixed contact 29 inasmuch as switch 26 is actuated to that position by normal inflation pressure within gasket 15. V

of my circulating means and said drain means; means for sealing said opening comprising an inflatable gasket on said cover adapted to sealingly engage said tub, a fluid inlet conduit communicating with said gasket, a solenoid valve in said inlet conduit, a circuit for energizing said solenoid valve including a manually operable switch and a pressure switch responsive to the pressure in said gasket, said pressure switch having a movable contact normally engaged with a first contact connected in circuit with said solenoid valve but movable inire sponse to a predetermined pressure in said gasket into engagement with a for sequentially controlling the energization of said fluid circulating means and said drain means; means fQIfSofil-f ing said opening comprising an inflatable gasket on said V In describing the operation of my invention, itrwill be assumed that dishes or other articles to be washed have 7 been placed in suitable racks (not shown) in tub 2 and that the dishwater has been prepared for washing, the Timer 13 is, of course, set so as to start the washing cycle and push-button 29b is then depressed so as to close vent valve 19 and complete a circuit through power supply line L interlock switch 25, master switch 24, main power switch 13a, contacts 27 and 28 or" pressure switch 26 and through inlet valve 7 to power supply line L thus opening valve 7'and admitting water through inlet conduit 6.- Gasket 15 is immediately inflated with water so as to seal cover 5 to tub 2, and pressure switch 26 then actuates mo'va-ble contact 27 into engagement with fixed contact 29. Power is thereupon supplied to timer contacts 22, 23.-which control the impeller motor'and the drain pump respectively, as Well as timer switch 21 which controls operation of inlet valve 7 during normal washing operations. Since timer 13 was initially set to start a washing cycle, switch 21 maintains valve 7 in its open position so as to fill tub 2, and thereafter switches 21, 22 and 23 operated in their usual manner so as to provide a complete washing operation During the entire washing cycle vent valve 19 is, of course, closed and hence sealing pressure is maintained, in gasket 15. However, if for any reason pressure in gasket 15 should decrease (for example, as the result of malfunctioning of one of the valves in the system) pressure switch 26 will bereturned to the position shown in Fig. 3 soas to momentarily open inlet valve 7 and again build up sealing pressure in the gasket. Thus the seal between cover 5 .and tub 2 will be maintained throughout the washing operation.

After the washing operation has been com pleted timer switches 13a, 21, 22 and 23 are opened thus de-energizing valve 7, impeller motor 11 and'drain pump 12. To open tub 2, pushbutton Zita is depressed so as to open switch 24 and vent valve 19, thus relieving the pressure in gasket 15, whereupon sealing surface 16 of the gasket moves out of engagement with flange 17 of the tub. a a

While I have shown and described a specific embodiment of my invention, I do not wish my invention to be limited to the particular construction shown and described, and I intend by the appended claims to cover second contact connected in a circuit for energizing timer means, and manually controlled means for draining said ga k 7 1 v 2.-In a dishwasher of the type including a tubhaving a top access opening, a cover for said opening, motor driven means for circulating fluid in said tub, electrically energized means for draining'said tub, and timer means cover adapted to sealingly engage said tub, a fluid inlet conduit communicating with said gasket, a discharge conduit communicating with said gasket and with said tub,

a solenoid valve in said inlet conduit, a pressure relief valve in said discharge conduit adapted to maintain predetermined pressure in said gasket, a vent valve connecting said gasket and said discharge conduit, a circuit for energizing said solenoid valve including a manually operable switch and a pressure switch responsive tothe pressure in said gasket, said pressure switch having: a'

movable contact normally engaged with a first Contact connected to circuit with said solenoid valve but movable in response to a predetermined pressure in said gasket into engagement with a second contact connected circuit with said timer means, and manually-operable means for actuating said vent valve so as to deflate said; ask

3. In a dishwasher or the like of the type comprising a a tub having a top access opening, 'a cover including a peripheral sealing surface for said opening, hydraulic means associated with said cover for movingrsaid sealing surface into engagement with said tub, motor-drivenmeans for circulating fluid in said tub, electrically energized means for draining said tub, and timer means for sequentially controlling the energization of said fluid circulating means and said drain means; a fluid inlet conduit communicating with said hydraulic means, a

solenoid valve in said inlet conduit, a circuit for energi zing said solenoid valve including 'a manually operable switch and a pressure switch responsive to the pressure in said hydraulic means, said pressure switch having a movable contact normally engaged with a-first .con-

tact connected in circuit withsaid solenoid valve butimovable in response to a predetermined pressure insaid hydraulic means into engagement with a second con.,

tact connected in circuit with said timer means, and

manually operable means for deflating said gasket.

4. In a dishwasher or the like of the type comprising a tub having a top access opening, a cover including a type including a tub havconduit communicating with said hydraulic means, a discharge conduit communicating with said hydraulic means and with said tub, a solenoid valve in said inlet conduit, a pressure relief valve in said discharge conduit adapted to maintain a predetermined pressure in said 5 gasket, a vent valve connecting said gasket and said discharge conduit, a circuit for energizing said solenoid valve including a manually operable switch and a pressure switch responsive to the pressure in said hydraulic means, said pressure switch having a movable contact 10 normally engaged with a first contact connected in circuit with said solenoid valve but movable in response to a predetermined pressure in said hydraulic means into engagement with a second contact connected in circuit with said timer means, and manually operable means for actuating said vent valve so as to reduce the pressure in said hydraulic means to atmospheric pressure.

References Cited in the file of this patent UNITED STATES PATENTS 

